ANKARA, Turkey — President Recep Tayyip Erdogan of Turkey on Wednesday approved new leaders for the army, navy and air force, in the biggest reshuffling since he won new powers for the presidency in a referendum in April.

The appointments come amid a continuing government purge of officers and civilians suspected of participating in a failed coup last year, but also as part of a longer term effort to impose civilian control over the once-dominant Turkish military.

The new appointments prepare the ground for the succession to the top military post, the chief of staff. Gen. Hulusi Akar, the current chief of staff, remains in his post, but one of the three newly appointed armed forces chiefs are likely to replace him when he retires. Usually the commander of the Turkish Army is chosen.

General Akar, who was taken hostage by rogue officers during the failed coup in July 2016, is scheduled to retire in 2019, a critical year because the changes approved in the referendum will allow the winner of the 2019 presidential election to assume full control of the government, ending the current parliamentary political system.

Government supporters and secularist-nationalists appeared to welcome the military appointments. Two of the new chiefs were also taken hostage during the failed coup, and their selection was interpreted as a reward for their loyalty as well as a recognition of their abilities.

The Supreme Military Council, which was once a secretive military body but now consists of senior military officers and cabinet ministers, made the appointments, said Ibrahim Kalin, a presidential spokesman. Prime Minister Binali Yildirim is the chairman of the military council.

Mr. Erdogan approved the appointments and met with the commanders later in the day, Turkish news agencies reported.

Murat Kelkitlioglu, editor in chief of a pro-government daily newspaper, Aksam, praised the new form of the military council in a message on Twitter. “This is how a civilian Supreme Military Council happens!’’ he wrote. “Instead of 4 days, it take 4 hours! It does not keep busy for a week! If it is required, the top command can be changed!”

A retired rear admiral, Semih Cetin, offered praise for three other senior naval appointments announced by the council on Wednesday, saying on Twitter that three colonels who had been targets in an earlier purge by opponents of Mr. Erdogan had been promoted to the rank of admiral.

Yet resistance to civilian control remains inside military circles. Nusret Guner, a vice admiral who resigned in 2013 to protest an earlier crackdown on the army, said in a Twitter message that the country’s military had now become “totally intertwined with politics.’’

“Turkey’s done for,” he added.

The military council selected Yasar Guler, currently commander of the gendarmerie, to take over command of the army. It also appointed Vice Adm. Adnan Ozbal to be commander of the navy, and Hasan Kucukakyuz will command the air force.

It is not clear if the departing commanders were scheduled for retirement or are being replaced early.

Mr. Erdogan’s government has been overseeing a large-scale purge of the army and other institutions since the attempted coup last year, when a renegade group of military officers tried to seize power, sending tanks into the streets and bombing the Parliament building.

In all, 249 people died during the uprising, for which the government has blamed followers of the Islamist cleric Fethullah Gulen, who was once allied with Mr. Erdogan but is now living in self-imposed exile in Pennsylvania. He is being tried in absentia for the plot; he has denied the charges.

The government has discharged 169 generals and admirals, almost half of the senior ranks a year ago, and arrested 7,000 military personnel in a crackdown. Tens of thousands of civilians, including government workers, members of Parliament and journalists, have also been detained and charged with aiding the Gulenists.

A trial of nearly 500 people accused of being involved at the plot’s headquarters at the Akinci Air Base began on Tuesday at a court in a prison near Ankara, the capital. Among the defendants, in addition to Mr. Gulen, is a former commander of the air force, Akin Ozturk. The charges include murder, violating the Constitution and trying to kill the president.

A version of this article appears in print on , on Page A6 of the New York edition with the headline: Turkey Picks New Officers For Top Posts In the Military. Order Reprints | Today’s Paper | Subscribe